Chapter 15-17 Flashcards
Acids Empirically Defined
Substances that Taste sour Conduct electricity React with metals to produce hydrogen gas Turn blue litmus paper red PH ranges between zero and seven
Bases empirical definition
Are Substances that: Taste bitter Conduct electricity Feel soapy or slippery PH ranges between seven and 14
Svante Arrhenius
He offered an explanation for the difference in behaviour between acids and bases
Arrhenius theory acids
Acids produce hydrogen ions when they are dissolved in water. Asses are substances that ionize in aqueous solution to form hydrogen ions
Note: the hydrogen ions are responsible for the acidic properties of these solutions
Arrhenius Theory bases
Bases produce hydroxide ions when they are dissolved in water. Faces are substances that dissociate to form hydroxide ions in aqueous solution.
Note: the hydroxide ions are responsible for the basic properties of these solutions
Hydronium Ions
The hydrogen Ion does not exist on its own but bonds to polar water molecules.
Hydrated protons, H3O+ (aq) is called a hydronium ion
Is responsible for acidic properties
Acid Rules
Can be identified because the hydrogen ion is written first in the formula
Exception: acetic acid (CH3OOH(aq))
Acids are always given the state aqueous (aq)
Naming acids
The IUPAC name consist of three words: aqueous hydrogen and the name of the Anion Example: aqueous hydrogen chloride Classic rules to name acids: Hydrogen\_\_\_ide becomes hydro\_\_\_ic acid Hydrogen\_\_\_ate becomes \_\_\_\_\_\_\_\_\_ic acid Hydrogen\_\_\_ite becomes \_\_\_\_\_\_\_\_ous acid
Acids bases and ionic substances
To distinguish between these substances we use simple diagnostic tests
Litmus test
Used primarily to distinguish acids from bases
Red litmus turns blue if a base
Blue litmus turns red if an acid
Conductivity test
Used to determine if a solution is ionic acidic basic or if the solution is molecular
If a solution conducts electricity it is either ionic, acidic, or basic
If a solution does not conduct electricity the solution contains a molecular compound
More dissolved ions will be more conductive then a solution with fewer dissolved ions
Indicators
Substances that change colour when the acidity of the solution changes are called acid base indicators
These chemicals exist in at least two different forms each with a distinct colour
Higher and lower pH
The Lower PH form (more acidic) is denoted as HIn (aq)
The higher pH form (more basic) is In-(aq)
Common indicators
Litmus paper: red in acid, blue in base
Bromothymol blue: yellow in acid, blue in base
Phenolphthalein: clear in acid, pink/purple in base
PH paper
PH paper will give an exact pH of the substance being tested, it not only indicate acidic or basic but the actual PH
Note: you can use information from various indicators to determine the pH of an unknown sample